Prewarrant thermal imaging as a Fourth Amendment violation: a Supreme Court question in the making.

• Author: Kash, Douglas A.

1. INTRODUCTION

   Over the last few years, a new issue in criminal procedure has begun taking shape. The issue involves the legality of using a "thermal imaging device" that can measure the heat emanating from a private residence. The device is used by police to detect heat generated by indoor marijuana growing operations. The majority of courts have ruled that the warrantless use of a thermal imager does not raise Fourth Amendment concerns.(1) Relatively few courts have ruled that the use of these devices without a warrant violates the Fourth Amendment protections against unreasonable searches.(2) Eventually, the Supreme Court will have no choice but to address this issue and rule on the side that has the support of prevailing constitutional analysis. While police are obliged to utilize advanced, but legal, law enforcement techniques in their pursuit of legitimate objectives, their ability is governed by the right of an individual to remain free from an unjustified governmental intrusion.(3) It is the job of the Supreme Court to consider these divergent ideologies and render a judicial interpretation of the law.

   Although the United States law enforcement community seems to be targeting the cocaine trade, marijuana has enjoyed a brief respite from police scrutiny. Due to the lack of national surveys in 1995, it is difficult to estimate the amount of domestically grown marijuana. It is known, however, that 3.27 million cultivated plants were destroyed in 1995, accounting for 1486 metric tons, and federal seizures amassed another 480 metric tons; federal authorities also seized 3348 indoor grow operations each of which, on average, cultivated 68 plants.(4) The six leading States for indoor growing activity included California, Oregon, Florida, Colorado, Georgia, and Washington, which cumulatively accounted for fifty-nine percent of the total indoor plants seized domestically.(5) The growers have more advanced technology enabling them to produce greater crop yields of a more potent plant than in previous years. The resulting emphasis on marijuana growers by anti-narcotic agents, and their successes, have caused the growers to go underground, both literally and figuratively, to avoid detection.

   Although smaller than outdoor fields, indoor operations are well-equipped "with the latest computerized irrigation systems, hydroponic basins, heating systems [and] growing lamps," which allow for four full growing cycles per year.(6) However, the advanced technology of the grower is also his weakness because it offers an exploitable advantage to law enforcement. Indoor growing operations require high intensity grow lamps that can generate temperatures up to 150 degrees Fahrenheit.(7) The heat must be exhausted from the operation in order to maintain the optimum temperature of 60 to 70 degrees Fahrenheit.(8) Police can take advantage of this necessity by using thermal imaging devices to detect the heat emissions.(9) The information gleaned will be used to establish probable cause in order to obtain a search warrant.(10) This tactic, however, requires the police to, at a minimum, briefly consider the Fourth Amendment limitations imposed on them by the Constitution.

   The Fourth Amendment was an effort by the Framers of the Constitution to provide protection against the abuses of the British General Warrants and the Writs of Assistance of colonial America.(11) "These arbitrary instruments authorized law enforcement officials to indiscriminately search and seize individuals' personal property, usually with dubious justifications."(12) Some scholars have identified these searches as "`the first in the chain of events which led directly and irresistibly to revolution and independence.'"(13)

   As stated in a previous analysis on the issue of a warrantless thermal scan:

   It is said that "a man's house is his castle," at least when it

   comes to governmental intrusion. If so, the castle's protective

   moat has been drained and paved smooth, its protective walls

   are rife with gaping holes through which the enemy can peer,

   and the skies above its ramparts are filled with airborne

   enemies. The castle -- once a treasured haven of personal

   privacy -- now stands vulnerable to an assault that threatens

   to dislodge its very foundation.(14)

   The strength of this phrase highlights the importance of the issue and the urgent necessity of its interpretation by the Supreme Court.

   This Article will provide an analysis of both sides of the issue. As indicated by its title, the Supreme Court likely will hear these arguments in the future. As will be illustrated later in this Article, because one of the more recent appellate decisions contradicted all previous appellate decisions,(15) the thermal imaging question is "heating up." This Article will attempt to offer an unbiased perspective of the issue, and allow the reader to draw his own conclusions.

2. How Thermal Imaging Devices Work

   Thermal imaging devices measure heat emanating from a structure by utilizing optical electronic sensors which can read the thermodynamic characteristics of the target.(16) These devices, about the size of a standard 35mm camera, can detect temperature differences as small as one-half of a degree at a range "between 2 feet [and] one quarter of a mile."(17) By scanning the infrared wave lengths of the electromagnetic spectrum (which contains many types of energy fields), a heat temperature can be recognized and measured.(18) Since the infrared section of the spectrum occurs at significantly lower speed than that of visible light, it cannot be seen with the human eye.(19) These imagers convert the thermal readings to a computer which generates several types of displays including still, video or real-time pictures.(20)

   Thermal energy is generated by radiated heat, not convected heat.(21) The heat radiates until it is reflected, absorbed or transmitted. "In the same way that a window and a curtain will allow different amounts of light to pass through them, different materials allow different amounts of heat to radiate from them. Hot objects appear white because they radiate more infrared energy than cold objects, which appear dark."(22) Essentially, the imagers are passive devices which do not send out any type of pulse, ray or beam into a structure but instead target and measure emanating heat ("waste heat").(23) The device is employed beyond the curtilage and thus does not intrude in any fashion onto or into the targeted property. The imager detects hot spots on the exterior of a building which could be observed by any member of the public equipped with a commercially available device.(24) Before using the device, the operator must wait until night-fall in order to allow solar energy stored in the target to dissipate.(25) The operator then focuses on a normal heat source, such as an active chimney, to calibrate the device. Once the operator targets the suspected structure in an effort to "see" the heat patterns, constitutional issues under the Fourth Amendment are implicated; however, the courts differ as to the resolution of the issue.(26)

3. A Thermal Imaging Case Analysis of the Fourth Amendment

   The Fourth Amendment to the United States Constitution offers protection to U.S. citizens from unreasonable searches of their inherent privacy. The Fourth Amendment provides:

   The right of the people to be secure in their persons,

   houses, papers and effects, against unreasonable searches and

   seizures, shall not be violated, and no Warrants shall issue,

   but upon probable cause, supported by Oath or affirmation,

   and particularly describing the place to be searched, and the

   persons or things to be seized.(27)

   The amendment requires police to apply for an receive a warrant from a neutral magistrate who reviews the application and supporting affidavit to determine whether probable cause has been established.(28) Under Mapp v. Ohio,(29) any evidence obtained during

   Until the Supreme Court decision in Katz v. United States,(41) Fourth Amendment protections extended only to persons and places.(42) The Katz court pointedly stated that "the Fourth Amendment protects people, not places."(43) Factually, the Katz decision held that even though a telephone booth is considered a public place, the speaker is entitled to assume that the conversation is private.(44) The booth becomes a temporary haven, a private place which is entitled to security from interception of conversations, unless probable cause has been demonstrated to a magistrate, in which case the magistrate can issue a warrant.(45) The Court held that through electronic surveillance, the Government "searched and seized" the booth occupant's conversation in violation of the Fourth Amendment.(46)

   Justice Harlan's concurrence provided a two-part test to determine if the Fourth Amendment applies to a specific situation.(47) First, does the defendant exhibit an actual (subjective) expectation of privacy (has the individual shown that he seeks to preserve something as private)? Second, if so, is such an expectation one that society would recognize as reasonable objective)?(48) This two-part inquiry has come to be known as the "reasonable expectation of privacy," test(49) and has led to the present impasse as it relates to new technology. Fortunately, the Framers provided an amendment broad enough to apply to inconceivable technologies over 200 years in their future.

4. Thermal Imagers Do Not Raise Fourth Amendment Issues

   The current dilemma among the federal courts is whether the use of a thermal imager is subject to a Fourth Amendment application and analysis. The Seventh and Eighth Circuits adopted the analysis(50) set forth in United States v. Penny-Feeney,(51) which held that the use of a thermal imaging device is not a search within the meaning of the Fourth Amendment. The Eleventh Circuit also reached the same conclusion.(52) Most illustrative of the present reluctance to take on these issues are several opinions in which the...